Oh what a difference one word can make. Take away the “West” from “West Virginia,” and you have a once-red state that surely is now purple, a state carried twice by Barack Obama. But add back the “West” and you have the Mountain State, which has been headed down a different path over the past dozen years from its neighbor to the east.

West Virginia is a once-Democratic state that has moved decisively toward the Republican column, at least in federal races. And that is why, more than anything else, it looks to be not merely a good GOP Senate pickup opportunity upon Sen. Jay Rockefeller’s retirement but an excellent one.

Al Gore (2000), John Kerry (2004) and Obama (2008 and 2012) each lost West Virginia in presidential races, with Obama losing it in his re-election contest by almost 27 points: 62.3 percent for Mitt Romney and 35.5 percent for the sitting president.

If the Republican brand has suffered significantly nationally over the past four years, the national Democratic brand has eroded just as dramatically in West Virginia. Guns helped move the state away from the Democratic column initially, in 2000, but the Obama administration’s perceived hostility to coal has added to the party’s problems in the state.

Democrats still hold the state legislature, and most of the state’s top statewide offices — only the attorney general is a Republican — but two of the state’s three members of the U.S. House are Republicans.

West Virginia Senate seats have not seen competitive races recently. The late Democratic Sen. Robert C. Byrd served eight full terms and part of a ninth before he died in June 2010. Voters selected then-Gov. Joe Manchin III, a Democrat as conservative on guns and the environment as almost any Republican, to fill the rest of Byrd’s term. Manchin won a full term in 2012.

Rockefeller, 75, has served five full terms in the Senate, and his retirement was not unexpected.

If the dynamics of West Virginia politics make Rockefeller’s 2014 open seat a GOP opportunity, it is the candidacy of Republican Rep. Shelley Moore Capito that makes the eventual Democratic nominee start as an underdog in the race.

Capito, 59, was first elected to Congress in 2000, and she has been racking up huge re-election margins in recent years. Her district, which was considered a swing seat when she first won it, starts in the eastern panhandle and stretches west across the middle of the state all the way to the Ohio River, taking in Charleston, the state capital.

The Club for Growth released a statement almost immediately after Capito announced that she would run for the Senate next year (Rockefeller had not yet announced his retirement), attacking her as an “establishment” Republican who voted “to bail out Fannie Mae and Freddie Mac, for massive expansions of government-run health insurance, giveaways to big labor, and ... funding for wasteful earmarks like an Exploratorium in San Francisco and an Aquarium in South Carolina.”

But while the Club for Growth and the GOP’s tea party wing have been effective in many states and primaries, West Virginia seems like a less hospitable place for their efforts.

“Republican voters in the state are social conservative more than they are economic conservatives,” one veteran GOP consultant said. “Capito’s only problem would be if the state’s pro-lifers went after her, and there isn’t a lot of evidence now that that will happen.” Capito favors some abortion rights.

Democrats don’t yet have a top-tier candidate in the race, but a number of current and former officeholders are considering a run.

None, of course, has Capito’s lengthy record of electoral success (except for Rep. Nick J. Rahall II, who is unlikely to run), and any Democratic nominee will be burdened by Obama’s record.

The president did more than 3 points worse in West Virginia than he did in North Dakota last year, and Capito would start off against any Democrat with a clear lead in the polls, something that neither North Dakota Republican Rick Berg nor Indiana Republican Richard E. Mourdock did last cycle.

Manchin’s recent victories prove that a Democrat can win even with Obama in the White House, but Manchin had served in elective office for years, including as governor, and he had a strong image of independence. It’s unlikely any other Democrat most often mentioned as possible candidates — Secretary of State Natalie Tennant, Supreme Court Justice Robin Davis or former interim Sen. Carte P. Goodwin — would begin with similar strengths.

West Virginians are used to members of Congress who “bring back the bacon,” and Capito has the kind of profile that makes her a formidable candidate for the open Senate seat.

Democrats certainly shouldn’t count this seat lost yet. With a strong nominee and a possible suicide mission by anti-establishment conservatives who would rather elect a Democrat than Capito, anything could happen. Still, Democrats have reason to be worried about their ability to hold this seat next year.

Stuart Rothenberg (@stupolitics) is editor of the Rothenberg Political Report (rothenbergpoliticalreport.com).